Why Do You Block IPv6?

TL/DR: Private Internet Access does not use IPv6 as the current implementations are insecure and could potentially compromise your privacy and security.

What is IPv6 and how is it different to IPv4?

IPv4 is the 4th revision of the Internet Protocol (IP) which is used to identify devices on a network. Whilst IPv4 is the most widely deployed internet protocol it is a 32 bit system which means it only allows for 2^32 addresses, meaning there can be a maximum of 4,294,967,296 addresses or devices at any one time.

IPv6 is a 128 bit address system which allows for a significantly higher number of addresses or devices at a single time. By comparison this works out as:

While various strategies have been deployed to extend the shelf-life of IPv4, the internet will eventually be forced to move to IPv6 due to limited addresses. Adoption of IPv6, however, has been slow – mainly due to upgrade costs, backward capability concerns, and sheer laziness. Consequently, although all modern Operating Systems support IPv6, the vast majority of websites do not yet bother.

This has led websites that support IPv6 to adopt to a dual-tiered approach. When connected to an address that only supports IPv4, they will serve up an IPv4 address, but when connected from an address that supports IPv6, they will serve up an IPv6 address.

Unfortunately, most VPN software fails to direct IPv6 traffic through the VPN tunnel, so when you connect to an IPv6 enabled website, your browser will make an IPv6 DNS request outside the VPN, which is therefore handled by your ISP.

Private Internet Access offers IPv6 Leak Protection by disabling IPv6 traffic while on the VPN. This ensures that no IPv6 traffic leaks out over your normal internet connection when you are connected to the VPN. This includes 6to4 and Teredo tunneled IPv6 traffic. This will not block IPv6 on Windows XP if you have manually enabled it.

Our customers can opt to enable or disable the option, however disabling IPv6 Leak Protection may lead to a compromise in your privacy and security. We are currently evaluating, investigating and testing methods which would prevent leaks and ensuring privacy and security is maintained to our high standards whilst IPv6 is enabled.